How do I install an SSL Certificate on cPanel

I just purchased an SSL certificate through GeoTrust. Now I need to install it.

If, in cPanel, I go to SSL Manager, then into certificates it gives me a place to paste a new certificate but I can't figure out how to actually save it there. It seems to disappear when I leave the SSL Manager. Anyone have any idea what I am doing wrong? Am I even in the right place to install it?

Also, I have absolutely no experience using an SSL on my site. Can anyone tell me where I can find some basic information about how to use it? Right now I don't even know how to make, for example, a specific order page secure. I know that somehow if you go to that page it will change to the secure connection. But how?

Sorry, once again, if I sound like an idiot. Hey, if it walks like a duck....